A systematic review of 37 brain MRI studies demonstrated that exercise fatigue and heat stress alter brain structure and function, including decreased brain volume and altered sensorimotor activation.
Systematic Review (n=37)
Brain MRI techniques reveal that exercise, fatigue, and heat stress induce structural and functional changes in the brain, such as altered perfusion and connectivity.
The central nervous system, specifically the brain, is implicated in the development of exertional fatigue under a hot environment. Diverse neuroimaging techniques have been used to visualize the brain activity during or after exercise. Notably, the use of magnetic resonance imaging (MRI) has become prevalent due to its excellent spatial resolution and versatility. This review evaluates the significance and limitations of various brain MRI techniques in exercise studies-brain volumetric analysis, functional MRI, functional connectivity MRI, and arterial spin labeling. The review aims to provide a summary on the neural basis of exertional fatigue and proposes future directions for brain MRI studies. A systematic literature search was performed where a total of thirty-seven brain MRI studies associated with exercise, fatigue, or related physiological factors were reviewed. The findings suggest that with moderate dehydration, there is a decrease in total brain volume accompanied with expansion of ventricular volume. With exercise fatigue, there is increased activation of sensorimotor and cognitive brain areas, increased thalamo-insular activation and decreased interhemispheric connectivity in motor cortex. Under passive hyperthermia, there are regional changes in cerebral perfusion, a reduction in local connectivity in functional brain networks and an impairment to executive function. Current literature suggests that the brain structure and function are influenced by exercise, fatigue, and related physiological perturbations. However, there is still a dearth of knowledge and it is hoped that through understanding of MRI advantages and limitations, future studies will shed light on the central origin of exertional fatigue in the heat.
Tan et al. (Tue,) conducted a systematic review in Exertional fatigue in the heat (n=37). Brain MRI techniques was evaluated on Brain structure and function changes (volume, activation, connectivity, perfusion). A systematic review of 37 brain MRI studies demonstrated that exercise fatigue and heat stress alter brain structure and function, including decreased brain volume and altered sensorimotor activation.